Electrical power distribution systems often include overhead electrical power distribution lines mounted upon poles by a wide variety of mounting structure. Other distribution systems include underground distribution lines in which protected cables run under the ground surface. It is often necessary to take phase-to-phase voltage measurements across transmission lines while testing for induced or live power lines or equipment.
Known high voltage safety line detectors, meters and testers comprise high resistance probes connected in series with a calibrated panel meter to read the voltage across the phase-to-phase or phase-to-ground terminals. They are designed for use as safety tools by high voltage line maintenance workers to verify the status of the line or equipment as nominal, induced or de-energized. Known devices for providing such measurements include contact type and non-contact type. With contact type a reference probe or transmitter and a meter probe or receiver are connected in series with a cable as the loop is closed with load terminals.
Under normal conditions, a meter reading is valid only while the probes are electrically connected to load terminals. Once the probes are removed from the load terminals, the meter does not show the measured value. If long extension poles are being used, then the meter is spaced a distance from the lineman. This can make it difficult for the lineman to read the meter while taking measurements.
Existing meters have functionality to store the peak rms value of an AC voltage. However, these systems use a microcontroller approach which requires software development time, and additional hardware costs for the microcontrollers and analog to digital converters and the like. Moreover, these devices do not show true rms value of the voltage on the line. Instead, such devices are generally providing a calculated value based on peak voltage which does not correspond to the true rms value.
The present disclosure is directed to improvements in high voltage phasing voltmeters.